Comparison of three strains of diabetic rats with respect to the rate at which retinopathy and tactile allodynia develop

[摘要] Purpose: We compared three rat strainsto determine if different strains develop early-stage diabeticretinopathy or sensory neuropathy at different rates. Methods: Sprague Dawley, Lewis, andWistar rats were made diabetic with streptozotocin. Diabetic andnondiabetic animals had retinal vascular pathology measured at eightmonths of diabetes. The number of cells in the retinal ganglion celllayer (GCL), retinal function (using electroretinography [ERG]), andretinal levels of inducible nitric oxide synthase (iNOS),cyclooxygenase2 (COX2), and vascular endothelial growth factor (VEGF)were measured at four months of diabetes. Tactile allodynia wasassessed in hind paws at two months of diabetes. Results: Diabetes of eight months’duration resulted in a significant increase in retinal degeneratecapillaries and pericyte ghosts in Lewis and Wistar rats, but not inSprague Dawley rats. A significant loss of cells in the GCL occurredonly in diabetic Lewis rats, whereas Wistar and Sprague Dawley ratsshowed little change. Diabetes-induced iNOS and VEGF were statisticallysignificant in all strains. Cyclooxygenase 2 (COX2) was significantlyelevated in the Sprague Dawley and Wistar strains. Lewis rats showed asimilar trend, however, the results were not statistically significant.All strains tended to show diabetes-induced impairment of dark-adaptedb-wave amplitude, but only Sprague Dawley and Lewis strains had asignificant reduction in latency. All strains showed significanttactile allodynia in peripheral nerves. Conclusions: At the durations studied,Lewis rats showed accelerated loss of both retinal capillaries andganglion cells in diabetes, whereas diabetic Wistar rats showeddegeneration of the capillaries without significant neurodegeneration,and Sprague Dawley rats showed neither lesion. Identification ofstrains that develop retinal lesions at different rates should be ofvalue in investigating the pathogenesis of retinopathy.

[学科分类] 生物化学/生物物理